This example shows a simple grid of 50 black circles arranged in a flexible wrapping layout across the page. The page initially contains a single div element, and the JavaScript loop appends 49 additional div elements directly to the document body. The circles are styled with CSS for size, background color, and rounded corners. The code uses the vanilla DOM API (`document.body.append` and `document.createElement`) rather than D3 selections, though the D3 v6 library is loaded via CDN but not actively utilized in the displayed behavior.